It is a very harsh fact but its true. There is not much anybody can do unless the drinker does not drink. When the deamon gets hold of them its very hard for them to resist. alcoholics don't get "drunk" like we do and gain a tolerance for alcohol that would put me and you right under the table !
its a long hard road but counciling is I think the key, although that "deamon" may lay rooted way way back in their past only when that is resolved or at least reasoned out, only then is it possible to move on. I am so sorry to read of your loss but as I have tried to say please don't take it as any failiure on your part. Alcohol abuse is a terrible thing and we are all victims even if it is not us who get addicted to its effects.
I believe that alcoholics anonymous recognise the fact that knowing you have a problem is one of the major steps to overcoming alcoholism. support and patience is all that can be offered. Well, that and some decent alcohol-free drinks...
The first step to overcoming anything YOU wish to is realising that YOU dont want to be how YOU are.
If you are a gambler, dieter, spendaholic, or even a compulsive wanker, the first step to stopping what you feel is a problem is realising that very fact that you DO have a problem.